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AbstractMyotoxicity caused by snakebite envenoming emerges as one of the main problems of ophidic accidents as it is not well neutralized by the current serum therapy. A promising alternative is to search for efficient small molecule inhibitors that can act against multiple venom components. Phospholipase A2(PLA2) is frequently found in snake venom and is usually associated with myotoxicity. Thus it represents an excellent target for the search of new treatments. This work reports the effect of temperature in the inhibition of catalytic properties of PLA2from Bothrops brazilivenom by Rosmarinic (RSM) and Chlorogenic (CHL) acids through experimental and computational approaches. Three temperatures were evaluated (25, 37 and 50 °C). In the experimental section, enzymatic assays showed that RSM is a better inhibitor in all three temperatures. At 50 °C, the inhibition efficiency decayed significantly for both acids. Docking studies revealed that both ligands bind to the hydrophobic channel of the protein dimer where the phospholipid binds in the catalytic process, interacting with several functional residues. In this context, RSM presents better interaction energies due to stronger interactions with chain B of the dimer. Molecular dynamics simulations showed that RSM can establish selective interactions with ARG112B of PLA2, which is located next to residues of the putative Membrane Disruption Site in PLA2-like structures. The affinity of RSM and CHL acids towards PLA2is mainly driven by electrostatic interactions, especially salt bridge interactions established with residues ARG33B (for CHL) and ARG112B (RSM) and hydrogen bonds with residue ASP89A. The inability of CHL to establish a stable interaction with ARG112B was identified as the reason for its lower inhibition efficiency compared to RSM at the three temperatures. Furthermore, extensive structural analysis was performed to explain the lower inhibition efficiency at 50 °C for both ligands. The analysis performed in this work provides important information for the future design of new inhibitors.Communicated by Ramaswamy H. Sarma

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This study aimed to evaluate the in vitroanthelmintic effect of curcumin and curcumin-loaded emulsion (CLE) in controlling H. contortusin small ruminants. The emulsions of this work presented droplet sizes between 200 and 600 nm, zeta potential greater than |30| mV, and moderate polydispersity for 45 days. Drug-excipient compatibility was studied by Infrared Absorption Spectroscopy and Differential Scanning Calorimetry, demonstrating the absence of physicochemical incompatibilities. No macroscopic signs of physical instabilities were observed during the analysis period. The release profile of curcumin from emulsion was similar to the diffusion of free curcumin. CLE presented better fits to the models proposed by Higuchi and Korsmeyer-Peppas, while free curcumin followed the Fickian diffusion phenomenon. The CLE showed significant DPPH free radical scavenging capacity, presenting better results than those obtained for free curcumin and ascorbic acid. The ovicidal activity observed for encapsulated curcumin (EC50: 60.8 μg/mL) was significantly higher than that observed for free curcumin (EC50 > 8 mg/mL). The first-stage larvae of H. contortusable to hatch from eggs treated with CLE or free curcumin showed substantial morphological changes, such as damage to anatomical structures, cuticle detachment, and vacuole formation. Thus, it is estimated that CLE is a pharmaceutical product with the potential for the treatment of small ruminants hemonchosis.

In the present study, we aimed to develop and characterize a hydrogel formulation containing a proanthocyanidin polymer-rich extract of Commiphora leptophloeosand investigate its toxicity and antifungal effect in vitroand in vivoon Galleria mellonellainfected with Candida albicanslarvae. The extract (4%) was incorporated into a hydrogel formulation based on chitosan (1.0%) and poloxamer 407 (18%), and evaluated by physical (organoleptic characteristics, rheological tests, and texture profile analysis), chemical (proanthocyanidin content and pH), and microbiological parameters. Under the study conditions, the new hydrogel displayed good physicochemical and microbiological stability for 3 months at 25 °C. Both the extract and the hydrogel were evaluated regarding their safety and efficacy in vitroon uterine/endometrial epithelial cells (HEC-1A) and against Candidaspp. strains, as well as in vivoin the alternative model of acute toxicity and C. albicans-infection in G. mellonella. The results showed that the hydrogel is biocompatible with the vaginal environment, becoming more viscous with increasing temperature, and has higher antifungal potential compared to a free extract at all tested concentrations in vitro(2172–33.9 μg/mL), and in vivoat the dose of 125 mg/kg. Overall, the data provide evidence of the potential of the new hydrogel to be applied in treating vulvovaginal candidiasis.

ABSTRACTThe objective of this work was to evaluate the physiological characteristics of eucalypts growing alongside the signal grass species Urochloa brizanthaand U. decumbens(weeds). The experiment was conducted in a controlled environment using randomised blocks with four replications. Three different treatments were studied: no weeds, addition of U. brizanthaand addition of U. decumbens, with both weeds at a density of 50 plant m–2. Physiological characteristics were evaluated at 18, 38 and 48 days after transplanting (DAT) and root collar diameter and height of the plants were measured at 2, 22, 34 and 44 DAT. The coexistence of eucalypts with these two species of signal grass did not modify the physiological variables of the eucalypts at 18 DAT and 38 DAT. However, at 48 DAT, the eucalypts in the two weed treatments showed reduced photosynthetic activity. When with U. decumbens, the eucalypts showed reduced transpiration, CO2consumption, stomatal conductance and the ratio between internal carbon concentrations and atmospheric carbon concentrations. The root collar diameter was more sensitive to competition with weeds than was the total height of the plants. We conclude that both U. brizanthaand U. decumbenshave negative effects on physiological characteristics and growth parameters of the eucalypts at 48 DAT.